allow multimethods to be treated as interceptors

CHANGELOG.md

@@ -17,6 +17,7 @@ We use [Break Versioning][breakver]. The version numbers follow a `<major>.<mino
 **[compare](https://github.com/metosin/reitit/compare/0.5.15...master)**
 
 * Improved Reitit-frontend function docstrings
+* Allow multimethods to be interpreted as interceptors
 
 ## 0.5.15 (2021-08-05)
 

modules/reitit-core/src/reitit/interceptor.cljc

@@ -29,6 +29,11 @@
 
 (def ^:dynamic *max-compile-depth* 10)
 
+(defn- fn->interceptor-map [func]
+  {:name ::handler
+   ::handler func
+   :enter (fn [ctx] (assoc ctx :response (func (:request ctx))))})
+
 (extend-protocol IntoInterceptor
 
   #?(:clj  clojure.lang.Keyword
@@ -61,12 +66,12 @@
   #?(:clj  clojure.lang.Fn
      :cljs function)
   (into-interceptor [this data opts]
-    (into-interceptor
-      {:name ::handler
-       ::handler this
-       :enter (fn [ctx]
-                (assoc ctx :response (this (:request ctx))))}
-      data opts))
+    (into-interceptor (fn->interceptor-map this) data opts))
+
+  #?(:clj  clojure.lang.MultiFn
+     :cljs cljs.core.MultiFn)
+  (into-interceptor [this data opts]
+    (into-interceptor (fn->interceptor-map this) data opts))
 
   #?(:clj  clojure.lang.PersistentArrayMap
      :cljs cljs.core.PersistentArrayMap)

test/cljc/reitit/interceptor_test.cljc

@@ -31,6 +31,11 @@
 (defn handler [request]
   (conj request :ok))
 
+(defmulti multimethod-handler (fn [request] (get request :type)))
+
+(defmethod multimethod-handler :default [request]
+  (conj request :multi-ok))
+
 (defn create
   ([interceptors]
    (create interceptors nil))
@@ -210,11 +215,11 @@
           i5 {:compile (fn [{:keys [mount?]} _]
                          (when mount?
                            (interceptor ::i5)))}
-          chain1 (interceptor/chain [i1 i2 i3 i4 i5 handler] {:mount? true})
-          chain2 (interceptor/chain [i1 i2 i3 i4 i5 handler] {:mount? false})
+          chain1 (interceptor/chain [i1 i2 i3 i4 i5 handler multimethod-handler] {:mount? true})
+          chain2 (interceptor/chain [i1 i2 i3 i4 i5 handler multimethod-handler] {:mount? false})
           chain3 (interceptor/chain [i1 i2 i3 i4 i5] {:mount? false})]
-      (is (= [::enter_i1 ::enter_i3 ::enter_i4 ::enter_i5 :ok ::leave_i5 ::leave_i4 ::leave_i3 ::leave_i1] (execute chain1 ctx)))
-      (is (= [::enter_i1 ::enter_i3 ::enter_i4 :ok ::leave_i4 ::leave_i3 ::leave_i1] (execute chain2 ctx)))
+      (is (= [::enter_i1 ::enter_i3 ::enter_i4 ::enter_i5 :ok :multi-ok ::leave_i5 ::leave_i4 ::leave_i3 ::leave_i1] (execute chain1 ctx)))
+      (is (= [::enter_i1 ::enter_i3 ::enter_i4 :ok :multi-ok ::leave_i4 ::leave_i3 ::leave_i1] (execute chain2 ctx)))
       (is (= [::leave_i4 ::leave_i3 ::leave_i1] (execute chain3 ctx))))))
 
 (deftest interceptor-transform-test